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Biomedical subjects

N Shanmugasundaram

Publications and source records attributed to N Shanmugasundaram.

12 recordsLinked to original sources
PubMed2006

Design and delivery of silver sulfadiazine from alginate microspheres-impregnated collagen scaffold.

A reconstituted collagen scaffold impregnated with silver sulfadiazine (SSD) loaded alginate microspheres, capable of delivering the drug in a controlled manner has been developed. SSD-loaded alginate microspheres were prepared by modified water-in-oil emulsion technique through interfacial ionic gelation of alginate using CaCl2. The SSD-loaded microspheres were impregnated in pepsin-solubilized collagen, in situ, while inducing fibrillation and cast as thin scaffold. Morphological features of microspheres and microsphere-impregnated collagen were analyzed through SEM. Distribution homogeneity of impregnated microspheres, their in vitro behavior in (Dulbecco's modified minimal essential media) DMEM, and antibacterial efficiency against ATCC pathogens were determined. Initial drug load of 20% (w/w) with respect to alginate and 40% (v/v) of 2% alginate with respect to oil phase were found to produce microspheres of optimum drug entrapment (3%) and required size range (300-370 microm). In vitro drug release studies from the scaffold showed an initial burst release of 47.5% and a controlled release for 72 h with equilibrium concentration of 68.8%. SSD-loaded microspheres exhibited minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) levels of 32 and 40.2 microg/mL to both K. pneumoniae and E. coli respectively. P. aeruginosa showed MIC and MBC levels of 44.8 and 51.2 microg/mL respectively, while Staphylococcus aureus exhibited MIC and MBC at the same concentration range (57.6 microg/mL). The collagen-based scaffold impregnated with SSD-loaded alginate microspheres can deliver SSD in a controlled fashion, can control infection for extended time period with lesser dressing frequencies, and will enable easier assessment of wound.

Alginates↗
PubMed2005

Cytotoxicity studies of chromium(III) complexes on human dermal fibroblasts.

The cytotoxicity of certain Cr(III) complexes, such as [Cr(salen)(H(2)O)(2)](+), [Cr(edta)(H(2)O)](-), [Cr(en)(3)](3+), [Cr(ox)(3)](3-), [Cr(pic)(3)], and CrCl(3), which differ in ionic character and ligand environment in human dermal skin fibroblasts, has been studied. After 72 h of exposure to 100 microM doses of chromium(III) complexes, the order in which the complexes had an inhibitory effect on cell viability was [Cr(en)(3)](3+) > [Cr(salen)(H(2)O)(2)](+) > [Cr(ox)(3)](3-) > [Cr(edta)(H(2)O)](-) > [Cr(pic)(3)] > CrCl(3). Based on viability studies it was confirmed that [Cr(en)(3)](3+), a triply charged cation, inhibits cell proliferation, and therefore, it was chosen to carry out further investigations. [Cr(en)(3)](3+), at a dose of 50 microM, was found to bring about surface morphological changes, evidenced by cellular blebbing and spike formation accompanied by nuclear damage. TEM analysis revealed substantial intracellular damage to fibroblasts in terms of the formation of apoptotic bodies and chromatin condensation, thus reflecting cell death. FACS analysis further revealed DNA damage by formation of a sub-G(1) peak with 84.2% DNA as aneuploid DNA and arrest of the G(2) / M phase of the cell cycle. Cellular DNA damage was confirmed by agarose gel electrophoresis with the characteristic appearance of a DNA streak in DNA isolated from [Cr(en)(3)](3+)-treated fibroblasts. The proposed mechanism suggests the plausible role of Cr(V), formed as a result of oxidation of Cr(III) by cellular oxidative enzymes, in the cytotoxic response. Consequently, any Cr(III) complex that is absorbed by cells and can be oxidized to Cr(V) must be considered a potential carcinogen. This has potential implications for the increased use of Cr(III) complexes as dietary supplements and highlights the need to consider the cytotoxicity and genotoxicity of a variety of Cr(III) complexes and to understand the potential hazards of Cr(III) complexes encountered in research laboratories.

Apoptosis↗
PubMed2003

In vivo and in vitro evaluation of hair growth potential of Hibiscus rosa-sinensis Linn.

Petroleum ether extract of leaves and flowers of Hibiscus rosa-sinensis was evaluated for its potential on hair growth by in vivo and in vitro methods. In vivo, 1% extract of leaves and flowers in liquid paraffin was applied topically over the shaved skin of albino rats and monitored and assessed for 30 days. The length of hair and the different cyclic phases of hair follicles, like anagen and telogen phases, were determined at different time periods. In vitro, the hair follicles from albino rat neonates were isolated and cultured in DMEM supplemented with 0.01 mg/ml petroleum ether extract of leaves and flowers. From the study it is concluded that the leaf extract, when compared to flower extract, exhibits more potency on hair growth.

Administration, Topical↗
PubMed2003

Biocompatible collagen scaffolds from a human amniotic membrane: physicochemical and in vitro culture characteristics.

A reconstituted collagen membrane from human amnion has been investigated as a source of collagen matrix, which could be used as a substratum for culturing human fibroblasts. The suitability of pepsin-solubilized reconstituted human amniotic membrane, before and after cross-linking with chitosan, as a dermal matrix for culturing fibroblast was assessed by morphologic, physicochemical, cytotoxic and histochemical methods. Measurement of thermodynamic behaviour, by differential scanning calorimetric (DSC) and thermogravimetric analysis (TGA), and tensile strength suggested that the cross-linked membrane had sufficient elasticity to serve as an efficient dermal substrate for in vitro culture of fibroblasts. Fibroblasts cultured on the chitosan cross-linked collagen membrane had good adherence, retaining their morphology as indicated by microscopic analysis. Proliferation of fibroblasts. observed on this membrane affirms its non-toxic nature. These results support the application of reconstituted human amniotic collagen membrane as collagenous scaffolds to culture fibroblasts in vitro.

Amnion↗
PubMed2001

Collagen-chitosan polymeric scaffolds for the in vitro culture of human epidermoid carcinoma cells.

A biodegradable polymer scaffold was developed using collagen and chitosan, in the form of interpenetrating polymeric network (IPN), for in vitro culture of human epidermoid carcinoma cells (HEp-2, Cincinnati). Glutaraldehyde was used as cross-linking agent for the development of scaffold. Various types of scaffolds were prepared using different proportionate mixtures of collagen and chitosan solutions in the ratio of 3:7, 4:6, 5:5, 6:4 and 7:3 (collagen:chitosan). These scaffolds were fully characterized by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA). Equilibrium swelling studies were carried out in phosphate buffer of physiological pH (7.4) to study its swelling characteristics at slightly alkaline pH. The scaffold that showed optimum swelling property was selected as the best scaffold for performing in vitro culture studies. In vitro culture studies were carried out using HEp-2 cells, over the selected scaffold and its growth morphology was determined through optical photographs taken at different magnifications at various days of culture. The results of the above studies suggest that the scaffolds prepared from collagen and chitosan can be utilized as a substrate to culture HEp-2 cells and can also be used as an in vitro model to test anticancerous drugs.

Animals↗
PubMed1991

Fluorescein diacetate and ethidium bromide staining to determine the viability of Mycobacterium smegmatis and Escherichia coli.

The ability of the fluorescein diacetate and ethidium bromide fluorescent staining method to assess the percentage of viable bacterial cells in suspension was compared with the plate counting method. Mycobacterium smegmatis and Escherichia coli bacterial cell suspensions were incubated at 60 degrees C. At different time intervals samples were taken and the percentage of viable cells in each sample was assessed by the fluorescent staining method and compared with the plate counting method. The fluorescent staining method showed a positive correlation with the plate counting method. However, the viable counts by the plate counting method were lower than the staining method when incubated at 60 degrees C, indicating a lag period in the decay of enzymes after bacterial death. Hence, the fluorescent staining technique can be used to assess the trend of bacterial death rather than to assess to exact number of viable bacilli.

Colony Count, Microbial↗
PubMed1989

A simple method to quantitate circulating immune complexes in different diseases.

Immune Complexes are involved in the Pathogenesis of many diseases of varied aetiology such as autoimmune disorders, protozoal diseases, bacterial and viral infections. Quantitation of immune Complexes in these diseases can be used for diagnosis and to ascertain the prognosis. The simple method of precipitation by polyethylene glycol and quantitation by single Radial Immunodiffusion has been used in leprosy, syphilis, bacterial endocarditis and systemic lupus erythematosus (SLE). This method found significantly higher levels of circulating immune complexes (CICs) in erythema nodosum leprosum, culture positive bacterial endocarditis and SLE where CICs are known to play an important role in the pathogenesis.

Antigen-Antibody Complex↗
PubMed1989

Differential diagnosis of viral hepatitis based on hepatitis viral markers.

192 patients of acute viral hepatitis (AVH) from three different hospitals of Madras metropolitan area during November 1985 to January 1986 were investigated for serologic markers of hepatitis A virus (anti HAVIgM) and hepatitis B virus (HBsAg, HBeAg, anti HBcIgM and anti HBs) by Enzyme linked immunosorbent assay (ELISA). While the overall pattern of AVH in Madras as revealed from the study showed Hepatitis A to be 36.4%, Hepatitis B 34.4% and Non-A Non-B 29.1%, the pattern differed significantly when areawise categorisation was done. The major AVH type in Government General Hospital was Hepatitis B (48.9%). While it was hepatitis A (46.9%) in Government Stanley Hospital and Non-A Non-B (40.0%) in Military Hospital. Using anti HBcIgM marker of Hepatitis B Virus and anti HAVIgM it was possible to make out that 13.5% of the cases, currently suffering from hepatitis A were either HBV carriers (8.3%) or cases convalescing from a previous Hepatitis B attack (5.3%). Various combinations of HBV markers positivity were observed and their diagnostic significance inferred.

Biomarkers↗
PubMed1989

Studies on the pathogenicity of classical enteropathogenic Escherichia coli strains isolated from acute diarrhoea among children 0-5 years of age.

The mechanisms of pathogenicity in EPEC strains were studied in tissue culture. Escherichia coli was isolated as the predominant organism in the primary culture of 1293 (70.54%) diarrhoeal cases. 284 (90.44%) cases from the age group of 1-6 months showed Escherichia coli as the predominant organism. Classical Enteropathogenic Escherichia coli) were detected in 311 (24.05%) cases. Among EPEC isolates 277 (89.06%) did not produce either LT or ST 32(10.28%) produced LT or ST. 2 strains produced verotoxins belong to serotypes 0:86; K:61, 0:26; K:60, sero groups 0.86 :K:61, 0.142:K 86, 0.128:K 67, 0.126:K 71, 0125:K 70 0119:K69 showed localised adherence and serogroups 0111:K58-055:K59 showed both localised and diffused adherence to HeLa cells.

Acute Disease↗
PubMed1977

Antimicrobial resistance and incidence of R factor among Salmonella isolated from patients with enteric fever and other clinical conditions in Madras, India (1975-1976)

The incidence of transmissible drug resistance among Salmonella isolated from patients with enteric fever and other clinical conditions is reported. All of the Salmonella isolated were studied for antimicrobial resistance. Of the 336 strains, five were multiply resistant to drugs including chloramphenicol, and four of these strains transmitted resistance to Escherichia coli F-Lac+. Multiply drug resistant E. coli were isolated from 12 patients receiving chloramphenicol, and in seven cases the E. coli transmitted drug resistance to sensitive Salmonella isolated from the same patients. The occurrence of multiple drug resistance among Salmonella was not found to be restricted to a single serogroup, and multiple drug resistance in Salmonella paratyphi A in India is reported for the first time. Although the incidence of Salmonella carring R factor is negligible, the unpredictability of its occurrence poses a potential threat in a country where typhoid is endemic.

Chloramphenicol↗